PERFECT STRUCTURE REGIONS IN AMORPHOUS ARGON

The structure of molecular dynamic models of amorphous argon is invest igated by the Voronoi-Delaunay method. It is shown that the majority o f Delaunay simplices (determined by quadruplets of the nearest atoms) are ''perfect,'' i.e., close in their shape either to the ideal tetrah edron or to the ideal quartoctahedron. These two types of structural e lements are positioned in a correlated manner relative to each other, forming regions of a ''perfect'' structure which, however, is not crys talline. The regions themselves are separated by sections of an ''impe rfect'' structure in which the shape of simplicial atomic configuratio ns differs from the mentioned ideal forms.